diagnose-help please

rtidecucv

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Had glow plug relay switch installed on CUCV Blazer--worked great for a while/no issues. Tried to start again after holding relay button-engine just turns over & over-no start. WILL START/RUN ONLY WITH -yikes- the dreaded starting fluid.
Relay fuse good. Fuel filter not clogged.
ANy suggestions on a 6.2 diesel mechanic in Decatur, AL area ???? As always, thanks.
 

Warthog

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First question is why did you install a manual switch?

Sounds like you have burned out all of your glowplugs.

Do you have a ohmmeter and know how to use it? You will have to start testing the system to find out where the issues are.

The Electrical Troubleshooting section of the TM 9-2320-289-20 technical manuals has a great section on diagnosing the GP system.
 

rickf

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If you put in a manual switch and are using the original series glow plug then you cooked them. They will only handle full power for a fairly short time. That is why most go to the AC60 plugs.

Rick
 

PsycoBob

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I can't help with the mechanic, unfortunately. Any interest in troubleshooting?

To clarify, no-start no-run, unless fed ether- does it keep running if you stop feeding it ether? Is there any fuel smell coming from the exhaust as you keep cranking?

If not, suspect fuel solenoid or IP. If yes (even poorly, like the engine isn't happy about trying to run) suspect glow-plug system.

Fuel shutoff/IP is something I've never had break (at at least, I've never had to try fixing one) but glow-plugs seem to bork around me.

Does the relay click when you push the button? If not, check that relay has power & switch is grounding the relay properly. If you modded it so the switch puts power to a grounded relay, reverse that. :)

Do you have 24v power to the resistor-pack side of the relay? If you don't have full voltage, check connections & fusable link. Resistor pack may have failed, but I've not seen it yet.

Do you have any power to the glow-plug side when the relay clicks? If you have nearly full battery voltage to the GP side, you need new plugs or wiring. If you have no voltage at all, you need a new relay. Anything between 6-14v is ok, higher means you may have some bad plugs.

Check the glow plugs- I've seen a truck go from All-good to all-open in a day or two from the snowball effect. If you're running a switch, consider going to 24v HMMWV plugs without the resistor.

If it cranks normally, you probably have decent batteries.

As an addendum to the usual 2 rules about CUCV's (Rubber, replace it- electrical, clean it.) I'll add check each glow plug when you can- a single failure isn't noticeable, but it'll snowball ****ed quick.
 

trukhead

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NO EITHER, try WD-40 and be sure to distribute to all the ports under the air cleaner. Either+ 6.2 = kkkknoock knock broken:evil:
 

PsycoBob

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WD-40 worked back when it used propane/butane for propellant- new stuff doesn't, for hippy reasons. Still a kerosene base, but now it's 'greener' or some such.

Ether can be used, sparingly, if the glow-plug system's disabled & cold. A single working plug that's still warm will grenade the engine, as will using too much. How much is too much? Well, that's the (replacement 6.2) dollar question, isn't it? If you can't afford a new engine, don't use ether.
 

PsycoBob

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If your silicone spray is flammable, its definitely the propellant. The liquid itself is pretty inert, but works nice at collecting dust in the intake system. Silicone oil will not combust in a diesel, unless you've already melted the internals out of it.

Fun fact: silicone oil is used in antifoaming agents for engine oils & deep fryers. It's also found in some antigas medications. :-?
 

pbrstreetgang

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I am having this same problem.

I replaced glowplugs, doghead mod, and resistor bank switchover back in february '12 - disconncted everything from glow plug relay and cleaned up connections and hooked everything back up. Truck started and ran great.

two weeks ago had a battery take a dive so I replaced. Truck started and ran great.

This week, truck began having trouble starting. I would pull controller card, put it back in and truck would fire. Now it will not.

I have ordered a legacy card from CUCV electric that is on the way. Wired a manual switch to use in the mean time until I can replace card.

Cannot get truck started with switch. I have rewired according to directions on site, but will not function. Daily driver big time. I use my CUCV every single day, I drive my kids to school in it. Need it to run. Need help
 

Warthog

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Please explain the manual switch wiring, as there are some incorrect intructions that have been posted over the years.

The easiest way is to just add a wire to the light blue wire on the relay, run it to a switch and then to ground.

You need to verify that you are getting 12v at the pink wire when the key is on. If so then you can test the relay by just grounding the terminal with the light blue wire.
 

pbrstreetgang

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I did just that

Tapped into light blue to switch, grounded other side to switch

Momentary horn / button type switch

Relay on firewall clicks
Truck turns over but will not fire

Possible to have burned out plugs
 

Warthog

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Test the plugs. Using an ohm meter they should read ~1 to 3 ohms each
 
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Do you have power coming out of the relay when it is activated? A simple test light will tell. Then test at the plug terminals. Is everything clean? The terminals corrode quick on the firewall of both CUCV's I've owned. It pays to disassemble, clean, use fresh star washers and di-electric grease yearly. Depending on the glow plugs you have, you may have had one give out, then the others followed suit.
 

762luver

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I don't want to be "that guy", but when i got my '09 it had starting issues. I baught 1 or 2 of everything from CUCVTHE Elec and didn't need any of it. Follow the tech manul procedure from the TM and you will find the real problem.

CUCV Elec has a copy of the tech manual pages you need, with COLOR added. (Dude!!!)

Good Luck!
 

pbrstreetgang

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All gps tested fine at 1.3 ohms

Getting 12 volts at top, both middle terminals on gp relay
Nothing at bottom terminal

That could be the issue. Should have new controller card tomorrow
To test

But if relay is bad, that would explain why manual gp switch
Did not work
 

mistaken1

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If you have power at the top of the relay and you have no power at the bottom of the relay when the light blue wire is manually grounded then you most likely have a bad glow plug relay. Replace that first.
 
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